Impact of fumigation on soybean varieties against Rotylenchulus reniformis

• Main Authors: Kularathna, Manjula, Overstreet, C, McGawley, EC, Xavier, DM, Godoy, FMC
• Format: Article
• Language: English

Content Partner: Lincoln University. The reniform nematode (Rotylenchulus reniformis) is one of the major pests on both soybean and cotton in the southern USA. Yield losses from this nematode to soybean have been reported to be greater than from cotton. Resistance in soybean cultivars against reniform nematode is not consistent with different geographical isolates of the pathogen. Resistant soybean cultivars recommended for Louisiana are based on the evaluations done in Arkansas with their native reniform populations. Field experiments were conducted during 2014-2015 in Tensas parish Louisiana, to evaluate the response of nematicide on 18 soybean cultivars against endemic R. reniformis populations. These soybean cultivars were categorized as susceptible, moderately resistant and resistant, according to studies conducted in Arkansas. In 2014 trial, fumigated (1,3-dichloropropene) and non-fumigated treatments representing 9 cultivars were employed. Nematode population data were collected at-planting, midseason and at-harvest. Application of the nematicide significantly reduced nematode population levels at all three sampling intervals. Out of the 9 cultivars, Delta Grow 4940 and S11-20354 had the lowest reniform nematode populations without fumigation at midseason and at-harvest. The cultivar R04-1268 produced the highest nematode populations in the absence of fumigation at both midseason and at-harvest. In both the presence and absence of the fumigant, lowest yields were observed with R04-1268, MPG 4714N, and Asgrow 4534. In 2015, another 9 soybean cultivars were tested in the same field with and without the fumigant. Similar to 2014, nematode population data were collected at-planting, midseason and at-harvest. Application of the nematicide significantly reduced nematode population levels at all three sampling intervals following a similar trend from the previous year. In this study, Asgrow 5535, Dyna Grow s52RY75 and Delta Grow 5230 had the lowest reniform nematode populations without fumigation at-harvest. The cultivar Delta Grow 5625 produced the highest nematode populations at harvest in nematicide untreated plots and resulted in significantly lower yield. These studies indicated that even with a different reniform isolate, soybean cultivars considered as resistant were able to hold their resistant against a population of reniform nematode in Louisiana.